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U 40.30.20.10:5060 -> 10.20.30.40:5060
  REGISTER sip:sip.mydomain.com SIP/2.0..Via: SIP/2.0/UDP 40.30.20.10:5060;branch=z9hG4bK-8890bff6;rport..From: "123456" <sip:123456@sip.mydomain.com>;tag=e9
  cb2ff4bca8b074o0..To: "123456" <sip:123456@sip.mydomain.com>..Call-ID: 1da9d5f4-2eea4274@40.30.20.10..CSeq: 1 REGISTER..Max-Forwards: 70..Contact: "123456" <sip:43
  9100@40.30.20.10:5070>;expires=86400..User-Agent: Sipura/SPA941-4.1.8..Content-Length: 0..Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER....                
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U 10.20.30.40:5060 -> 40.30.20.10:5060
  SIP/2.0 100 Trying..Via: SIP/2.0/UDP 40.30.20.10:5060;branch=z9hG4bK-8890bff6;received=40.30.20.10;rport=5060..From: "123456" <sip:123456@sip.mydomain.com>;tag=
  e9cb2ff4bca8b074o0..To: "123456" <sip:123456@sip.mydomain.com>..Call-ID: 1da9d5f4-2eea4274@40.30.20.10..CSeq: 1 REGISTER..User-Agent: Asterisk PBX..Allow: INVITE, 
  ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO..Supported: replaces..Content-Length: 0....                                                                         
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U 10.20.30.40:5060 -> 40.30.20.10:5060
  SIP/2.0 401 Unauthorized..Via: SIP/2.0/UDP 40.30.20.10:5060;branch=z9hG4bK-8890bff6;received=40.30.20.10;rport=5060..From: "123456" <sip:123456@sip.mydomain.com
  >;tag=e9cb2ff4bca8b074o0..To: "123456" <sip:123456@sip.mydomain.com>;tag=as1a751133..Call-ID: 1da9d5f4-2eea4274@40.30.20.10..CSeq: 1 REGISTER..User-Agent: Asterisk
   PBX..Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO..Supported: replaces..WWW-Authenticate: Digest algorithm=MD5, realm="sip.silverbackasp.net", no
  nce="6cae897f"..Content-Length: 0....                                                                                                                                         
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U 40.30.20.10:5060 -> 10.20.30.40:5060
  REGISTER sip:sip.mydomain.com SIP/2.0..Via: SIP/2.0/UDP 40.30.20.10:5060;branch=z9hG4bK-7d11cece;rport..From: "123456" <sip:123456@sip.mydomain.com>;tag=e9
  cb2ff4bca8b074o0..To: "123456" <sip:123456@sip.mydomain.com>..Call-ID: 1da9d5f4-2eea4274@40.30.20.10..CSeq: 2 REGISTER..Max-Forwards: 70..Authorization: Digest use
  rname="123456",realm="sip.silverbackasp.net",nonce="6cae897f",uri="sip:sip.mydomain.com",algorithm=MD5,response="205a71d25e4d63aec36792afd1411a8b"..Contact: "123456" 
  <sip:123456@40.30.20.10:5060>;expires=86400..User-Agent: Sipura/SPA941-4.1.8..Content-Length: 0..Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER....         
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U 10.20.30.40:5060 -> 40.30.20.10:5060
  SIP/2.0 100 Trying..Via: SIP/2.0/UDP 40.30.20.10:5060;branch=z9hG4bK-7d11cece;received=40.30.20.10;rport=5060..From: "123456" <sip:123456@sip.mydomain.com>;tag=
  e9cb2ff4bca8b074o0..To: "123456" <sip:123456@sip.mydomain.com>..Call-ID: 1da9d5f4-2eea4274@40.30.20.10..CSeq: 2 REGISTER..User-Agent: Asterisk PBX..Allow: INVITE, 
  ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO..Supported: replaces..Content-Length: 0....                                                                         
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U 10.20.30.40:5060 -> 40.30.20.10:5060
  SIP/2.0 200 OK..Via: SIP/2.0/UDP 40.30.20.10:5060;branch=z9hG4bK-7d11cece;received=40.30.20.10;rport=5060..From: "123456" <sip:123456@sip.mydomain.com>;tag=e9cb
  2ff4bca8b074o0..To: "123456" <sip:123456@sip.mydomain.com>;tag=as1a751133..Call-ID: 1da9d5f4-2eea4274@40.30.20.10..CSeq: 2 REGISTER..User-Agent: Asterisk PBX..Allo
  w: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO..Supported: replaces..Expires: 600..Contact: <sip:123456@40.30.20.10:5060>;expires=600..Date: Mon, 04 
  Oct 2010 07:45:32 GMT..Content-Length: 0....                                                                                                                                  
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U 10.20.30.40:5060 -> 40.30.20.10:5060
  NOTIFY sip:123456@40.30.20.10:5060 SIP/2.0..Via: SIP/2.0/UDP 10.20.30.40:5060;branch=z9hG4bK7f7b70d8;rport..From: "asterisk" <sip:asterisk@10.20.30.40>;tag=as1b260b2
  4..To: <sip:123456@40.30.20.10:5060>..Contact: <sip:asterisk@10.20.30.40>..Call-ID: 13dd87c7778f84704c7617db3c68a315@10.20.30.40..CSeq: 102 NOTIFY..User-Agent: Aster
  isk PBX..Max-Forwards: 70..Event: message-summary..Content-Type: application/simple-message-summary..Content-Length: 95....Messages-Waiting: yes..Message-Account: sip:asteris
  k@10.20.30.40..Voice-Message: 2/0 (0/0)..                                                                                                                                  
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U 40.30.20.10:5060 -> 10.20.30.40:5060
  SIP/2.0 200 OK..To: <sip:123456@40.30.20.10:5060>;tag=dfe6c5f4d0521274i0..From: "asterisk" <sip:asterisk@10.20.30.40>;tag=as1b260b24..Call-ID: 13dd87c7778f84704c7617db3
  c68a315@10.20.30.40..CSeq: 102 NOTIFY..Via: SIP/2.0/UDP 10.20.30.40:5060;branch=z9hG4bK7f7b70d8;rport=5060..Server: Sipura/SPA941-4.1.8..Content-Length: 0....          
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